Manipulation of solid, semi-solid or liquid materials

• US 5,795,457 A
• Filed: 06/05/1995
• Issued: 08/18/1998
• Est. Priority Date: 01/30/1990
• Status: Expired due to Term

• Current Assignee: British Technology Group Ltd.
• Original Assignee: British Technology Group Ltd.
• Inventors: Burt, Julian Paul Hillhouse, Pethig, Ronald
• Primary Examiner(s): Tsang, Cecilia J.
• Assistant Examiner(s): DELACROIX MUIRHEI, CYBILLE
• Application Number:
  US08/461,070
• Time in Patent Office: 1,170 Days
• Field of Search: 204/547, 204/554, 204/643, 204/660
• US Class Current: 204/547
• CPC Class Codes: B03C 5/026 using open-gradient differential dielectric separation, i.e. using electrodes of special shapes for non-uniform field creation, e.g. Fluid Integrated Circuit [FIC]
• CPC Class Codes: C12M 35/02 Electrical or electromagnetic means, e.g. for electroporation or for cell fusion
• CPC Class Codes: C12N 13/00 Treatment of microorganisms or enzymes with electrical or wave energy, e.g. magnetism, sonic waves
• CPC Class Codes: C12Q 1/24 Methods of sampling, or inoculating or spreading a sample; Methods of physically isolating an intact microorganisms
• CPC Class Codes: G01N 33/5306 Improving reaction conditions, e.g. reduction of non-specific binding, promotion of specific binding
• CPC Class Codes: G01N 33/537 with separation of immune complex from unbound antigen or antibody
• CPC Class Codes: G01N 33/54393 Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding

Abstract

By applying two or more electrical fields (DC, AC, pulsed) of different characteristics to an electrode array on e.g. the wall of a treatment cell, particles suspended in liquid in the cell may be manipulated as desired on a microscopic scale, in particular by exploiting the dielectrophoretic properties of the particles. The particles may be solid, semi-solid or liquid, and may be of simple materials or may be biological particles such as whole cells or fragments thereof.

Claims

1. A method of promoting a desired reaction between particles suspended in a liquid, said method comprising steps of:

applying, at a first frequency, a first non-uniform electrical field to a region of said liquid from an electrode array; and

applying, at a second frequency, a second non-uniform electrical field to said region of said liquid from said electrode array substantially simultaneously with said application of said first non-uniform electrical field, said second non-uniform field being independent of said first non-uniform electrical field;

said first non-uniform electrical field and said second non-uniform electrical field promoting said desired reaction using dielectrophoretic forces on said particles; and

at least one of said first frequency and said second frequency being chosen to effect a negative dielectrophoretic force on only some of said particles suspended in said liquid.

2. A method according to claim 1, further comprising a step of:

modifying at least one of an electrical conductivity and a dielectric constant of at least one of said liquid and said particles to further promote said desired reaction.

3. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 1, wherein:

said electrode array includes parallel electrode pair.

4. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 1, said method comprising further steps of:

determining said first frequency to be a first value which causes a negative dielectrophoretic force on said only some particles suspended in said liquid; and

determining said second frequency to be a second value which causes a positive dielectrophoretic force on others of said particles other than said only some particles suspended in said liquid.

5. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 1, said method comprising further steps of:

determining said first frequency to be a first value which causes a negative dielectrophoretic force on said only some particles suspended in said liquid; and

determining said second frequency to be a second value which causes a negative dielectrophoretic force on others of said particles other than said only some particles suspended in said liquid.

6. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 1, said method comprising further steps of:

determining said first frequency to be a first value which causes a negative dielectrophoretic force on said only some particles suspended in said liquid; and

determining said second frequency to be a second value which causes a further negative dielectrophoretic force on said only some particles suspended in said liquid.

7. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 1, wherein:

said electrode array is interdigitated and creates field traps wherein at least some of said particles suspended in said liquid agglomerate using negative dielectrophoretic forces.

8. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 7, wherein:

said interdigitated electrode array is castellated.

9. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 7, wherein:

said interdigitated electrode array includes a repeating pattern array.

10. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 7, wherein:

said interdigitated electrode array forms an inter-engaged comb-like pattern with an extending portion of a first electrode lying between two oppositely extending and neighboring portions of a second electrode.

11. A method of promoting said desired reaction between said particles suspended in said liquid according to claim 7, wherein:

said electrode array is mounted on an external wall of a treatment cell, said treatment cell including perforations in said external wall to allow removal of particles effected by said desired reaction through said perforations.

12. A method of promoting a desired reaction between particles suspended in a liquid, said method comprising steps of:

applying, at a first frequency, a first non-uniform electrical field to a region of said liquid from an electrode array; and

superimposing, at a second frequency, a second non-uniform electrical field to said region of said liquid from said electrode array substantially simultaneously with said application of said first non-uniform electrical field, said second frequency being different from said first frequency, said second non-uniform field being independent of said first non-uniform electrical field;

wherein said first non-uniform electrical field and said second non-uniform electrical field promote said desired reaction using dielectrophoretic forces on said particles.

13. A method of promoting a desired reaction between particles suspended in said liquid, said method comprising steps of:

introducing a volume of said liquid, including said suspended particles, into a treatment cell provided with electrodes;

applying a first electrical signal to said electrodes to generate a redistribution of said particles under an effect of a first dielectrophoretic force;

applying, simultaneously with said first electrical signal, a second electrical signal to said electrodes, a frequency of said second electrical signal being different from a frequency of said first electrical signal,

wherein said frequency of said second electrical signal is chosen taking into account a dielectric constant and electrical conductivity of said particles and said liquid to produce a second dielectrophoretic force acting on said particles, said second dielectrophoretic force being different from said first dielectrophoretic force.

14. A method of promoting a desired reaction between particles suspended in said liquid according to claim 13, wherein one of said first electrical signal and said second electrical signal applies a negative dielectrophoretic force on only some of said particles suspended in said liquid.

15. A method of promoting a desired reaction between particles suspended in said liquid according to claim 13, said method further comprising:

modifying one of said electrical conductivity and said dielectric constant of one of said liquid and said particles.

16. A method of promoting a desired reaction between particles suspended in said liquid according to claim 13, said method further comprising:

determining said frequency of said first electrical signal to be a first value which causes a negative dielectrophoretic force on only some of said particles suspended in said liquid; and

determining said frequency of said second electrical signal to be a second value which causes a positive dielectrophoretic force on others of said particles other than said only some particles suspended in said liquid.

17. A method of promoting a desired reaction between particles suspended in said liquid according to claim 13, said method further comprising:

determining said frequency of said first electrical signal to be a first value which causes a negative dielectrophoretic force on only some of said particles suspended in said liquid; and

determining said frequency of said second electrical signal to be a second value which causes a negative dielectrophoretic force on others of said particles other than said only some particles suspended in said liquid.

18. A method of promoting a desired reaction between particles suspended in said liquid according to claim 13, said method further comprising:

determining said frequency of said first electrical signal to be a first value which causes a negative dielectrophoretic force on only some of said particles suspended in said liquid; and

determining said frequency of said second electrical signal to be a second value which causes a further negative dielectrophoretic force on said only some particles suspended in said liquid.

19. A method of promoting a desired reaction between particles suspended in a liquid, said particles including first particles and second particles, said method comprising steps of:

introducing a volume of said liquid, including said suspended particles, into a treatment cell provided with electrodes;

applying, at a first frequency, a first electrical signal to said electrodes to generate a redistribution of positions of said particles under an effect of a first dielectrophoretic force;

applying, at a second frequency different from said first frequency, while said particles occupy said redistribution of positions, a second electrical signal to said electrodes, said second frequency being chosen taking into account a dielectric constant and electrical conductivity of said particles and said liquid to produce a second dielectrophoretic force acting on said particles, one of said first and second electrical signals acting to apply a negative dielectrophoretic force on only said first particles, and the other of said first and second electrical signals acting to apply only one of a negative dielectrophoretic force and a positive dielectrophoretic force on both said first particles and said second particles.

20. A method of promoting a desired reaction between particles suspended in said liquid according to claim 19, said method further comprising:

modifying one of said electrical conductivity and said dielectric constant of one of said liquid and said particles.

21. A method of promoting a desired reaction between particles suspended in a liquid, said particles including first particles and second particles, said method comprising steps of:

introducing a volume of said liquid, including said suspended particles, into a treatment cell provided with electrodes;

applying, at a first frequency, a first electrical signal to said electrodes to generate a redistribution of positions of said particles under an effect of a first dielectrophoretic force acting on said first particles and said second particles, said first dielectrophoretic force being one of a positive dielectrophoretic force and a negative dielectrophoretic force;

applying, at a second frequency different from said first frequency, while said particles occupy said redistribution of positions, a second electrical signal to said electrodes, said second frequency being chosen taking into account a dielectric constant and electrical conductivity of said particles and said liquid to produce a second dielectrophoretic force acting on said particles, said second dielectrophoretic force being a positive dielectrophoretic force acting on one of said first particles and said second particles, and said second dielectrophoretic force being a negative dielectrophoretic force acting on the other of said first particles and said second particles.

22. A method of promoting a desired reaction between particles suspended in said liquid according to claim 21, said method further comprising:

modifying one of said electrical conductivity and said dielectric constant of one of said liquid and said particles.